Chiari type I malformation revisited: diagnosis and treatment

The clinical efficacy study of treatment to Chiari malformation type I with syringomyelia under the minimally invasive surgery of resection of Submeningeal cerebellar Tonsillar Herniation and reconstruction of Cisterna magna

Purpose

Discuss the clinical efficacy of treatment to Chiari malformation type I with syringomyelia under the minimally invasive surgery of resection of Submeningeal Cerebellar Tonsillar Herniation and reconstruction of Cisterna magna.

Methods

130 Chiari malformation type I with syringomyelia patients, divided into treatment group, literature group and control group, were collected to be treated under the monitoring of ultrasound in the surgery.

Results

6 months after operation, the lesions were decreased or disappeared, the symptoms were relieved obviously. According to MRI and Mimics 17.0 software, the volumes of Cisterna magna increased distinctly (P < 0.001), the proportions of brain in foramen magnum region were decreased (P < 0.001). Assessed by CCOS scale and Tator methods, the improvement rates of treatment group were 97.7% and 94.6%, the literature group and control group were 82.2% and 77.8%, respectively.

Conclusion

The efficacy of Chiari malformation type I with syringomyelia under the minimally invasive surgery of resection of Submeningeal Cerebellar Tonsillar Herniation and reconstruction of Cisterna magna is remarkable, and the complications are fewer. This surgery emphasizes recovery of tonsil of cerebellum and reconstruction of Cisterna magna and the circulation path of cerebrospinal fluid, which is a safe and efficient treatment.

Decompression in Chiari Malformation: Clinical, Ocular Motor, Cerebellar, and Vestibular Outcome

BACKGROUND

Treatment of Chiari malformation can include suboccipital decompression with resection of one cerebellar tonsil. Its effects on ocular motor and cerebellar function have not yet been systematically examined.

OBJECTIVE

To investigate whether decompression, including resection of one cerebellar tonsil, leads to ocular motor, vestibular, or cerebellar deficits.

PATIENTS AND METHODS

Ten patients with Chiari malformation type 1 were systematically examined before and after (1 week and 3 months) suboccipital decompression with unilateral tonsillectomy. The work-up included a neurological and neuro-ophthalmological examination, vestibular function, posturography, and subjective scales. Cerebellar function was evaluated by ataxia rating scales.

RESULTS

Decompression led to a major subjective improvement 3 months after surgery, especially regarding headache (5/5 patients), hyp-/dysesthesia (5/5 patients), ataxia of the upper limbs (4/5 patients), and paresis of the triceps and interosseal muscles (2/2 patients). Ocular motor disturbances before decompression were detected in 50% of the patients. These symptoms improved after surgery, but five patients had new persisting mild ocular motor deficits 3 months after decompression with unilateral tonsillectomy (i.e., smooth pursuit deficits, horizontally gaze-evoked nystagmus, rebound, and downbeat nystagmus) without any subjective complaints. Impaired vestibular (horizontal canal, saccular, and utricular) function improved in five of seven patients with impaired function before surgery. Posturographic measurements after surgery did not change significantly.

CONCLUSION

Decompression, including resection of one cerebellar tonsil, leads to an effective relief of patients' preoperative complaints. It is a safe procedure when performed with the help of intraoperative electrophysiological monitoring, although mild ocular motor dysfunctions were seen in half of the patients, which were fortunately asymptomatic.

Hemifacial spasm associated with type 1 Chiari malformation: a retrospective study of 13 cases

Hemifacial spasm (HFS) associated with type 1 Chiari malformation is particularly uncommon and is limited to isolated case report. The aims of this study were to report the clinical correlates of patients who had simultaneously HFS and type 1 Chiari malformation and to present the outcome of these patients treated with microvascular decompression (MVD) surgery. We retrospectively evaluated 13 patients who had simultaneously HFS and type 1 Chiari malformation among 675 HFS patients. Clinical features and radiological findings were collected from each patient and analyzed. All these 13 patients were surgically treated with MVD through retro-mastoid microsurgical approach, and postoperative outcomes were evaluated. A review of literature about this association was also provided. In this study, the frequency of type 1 Chiari malformation in HFS patients was 1.9 %. The clinical profile of this series of patients did not differ from typical form of primary HFS. MVD achieved satisfactory results in 11 patients (85 %) in short- and long-term follow-up. There was no mortality or severe complication occurred postoperatively. Although rare, clinician should be aware of the association of HFS and type 1 Chiari malformation and consider MVD as an effective surgical management.

Craniovertebral Junction Instability in the Setting of Chiari I Malformation

This article addresses the key features, clinical presentation, and radiographic findings associated with craniovertebral junction instability in the setting of Chiari I malformation. It further discusses surgical technique for treating patients with Chiari I malformation with concomitant craniovertebral junction instability, focusing on modern posterior rigid instrumentation and fusion techniques.

[Sudden onset vertigo: imaging work-up]

Vertigo and dysequilibrium are a frequent cause of medical consultation. Clinical evaluation is essential. Some cases of vertigo are diagnosed clinically while others require imaging, sometimes emergently (suspected stroke). MRI is the imaging modality of choice to assess the labyrinth (labyrinthitis? labyrinthine hemorrhage?), internal auditory canal (vestibular schwannoma? other tumor?…) and brain parenchyma including all structures of the auditory pathways: vestibular nuclei, vestibulocerebellar tract, tracts involved with ocular motricity, vestibular cortex… Multiple central etiologies exist: stroke, multiple sclerosis, tumor… However, some etiologies are best depicted with CT, especially lesions of the labyrinth: cholesteatoma, trauma, suspected dehiscence of the superior semicircular canal, suspected labyrinthine fistula… Finally, imaging may be negative (Benign Paroxysmal Positional Vertigo, Meniere's disease, vestibular neuritis, migraine…), merely reducing the differential diagnosis.

Concurrent Chiari decompression and spinal cord untethering in children: feasibility in a small case series

BACKGROUND AND PURPOSE

We describe the rationale and safety of concurrent decompression of Chiari type 1 malformation (CM1) and untethering of the spinal cord. Spinal cord traction is considered one of the pathogenic mechanisms involved in the development of CM, and 14% of patients with CM1 have tethered cord syndrome (Milhorat et al., Surg Neurol 7:20-35, 2009; Roth, Neuroradiology 21:133-138, 1981; Royo-Salvador, Rev Neurol 24:937-959, 1996; Royo-Salvador et al., Acta Neurochir 147:515-523, 2005). Therefore, intraspinal anomalies that require intervention are commonly treated before surgical decompression of Chiari malformation (Cheng et al., Neurologist 8:357-362, 2002; Menezes, Pediatr Neurosurg 23:260-269, 1995; Milhorat et al., Surg Neurol 7:20-35, 2009; Royo-Salvador et al., Acta Neurochir 147:515-523, 2005; Schijman and Steinbok, Childs Nerv Syst 20:341-348, 2004; Yamada et al., Neurol Res 26:719-721, 2004). However, in the interval between the spinal cord untethering and the decompression surgery, patients may continue to suffer from the untreated symptoms of CM. In a series of four patients with concurrent severe and progressive symptoms referable to both conditions, we performed both surgeries simultaneously.

METHODS

Charts of four patients who underwent concurrent Chiari decompression and spinal cord untethering were reviewed.

RESULTS

All patients tolerated the procedures well without complication. They reported significant or complete early postsurgical resolution of headaches and ambulating difficulties. On average, patients started to walk on postoperative day 3 (3 ± 1 days) and were discharged on hospital day 6 (6 ± 1 days). No patient experienced a persistent subcutaneous or transcutaneous cerebrospinal fluid leak. Subsequent postoperative courses were uneventful.

CONCLUSION

Concurrent Chiari decompression and untethering of the spinal cord is a feasible option and in some patients may be preferred in lieu of staged procedures.

Chiari type I malformation in children

The diagnosis of Chiari type I malformation (CIM) is more and more frequent in clinical practice due to the wide diffusion of magnetic resonance imaging. In many cases, such a diagnosis is made incidentally in asymptomatic patients, as including children investigated for different reasons such as mental development delay or sequelae of brain injury. The large number of affected patients, the presence of asymptomatic subjects, the uncertainties surrounding the pathogenesis of the malformation, and the different options for its surgical treatment make the management of CIM particularly controversial.This paper reports on the state of the art and the recent achievements about CIM aiming at providing further information especially on the pathogenesis, the natural history, and the management of the malformation, which are the most controversial aspects. A historial review introduces and explains the current classification. Furthermore, the main clinical, radiological, and neurophysiological findings of CIM are described to complete the picture of this heterogeneous and complex disease.

Young onset Hemifacial Spasm in patients with Chiari type I malformation

Hemifacial spasm (HFS) resulting from Chiari type I malformation (CIM) is rare. We retrospectively evaluated five patients with CIM and HFS among a series of 103 subjects. The frequency of HFS associated to CIM was of 4.85%. The clinical profile did not differ from the classical primary cases except for young-onset development of facial spasms in patients with CIM. Three patients were treated with BTX-A injections with favorable outcome. Although rare HFS may be associated with CIM especially in young subjects with peculiar phenotypic characteristics (short neck). Moreover, BTX may be an alternative to posterior fossa decompression in selected cases.

Variations of the position of the cerebellar tonsil in idiopathic scoliotic adolescents with a cobb angle >40 degrees: a magnetic resonance imaging study

STUDY DESIGN

A retrospective study was performed through measurements on MRI images in adolescent idiopathic scoliosis (AIS) patients and age-matched adolescents.

OBJECTIVES

To investigate the position of the cerebellar tonsil in AIS patients with a Cobb angle >40 degrees in comparison with age-matched healthy adolescents and to determine the relationships of the tonsil position with age, sex, curve severity, and curve patterns.

SUMMARY OF BACKGROUND DATA

There have been increasing evidences implying that AIS patients may present with subtle or subclinical neurologic dysfunction and a higher incidence of tonsillar ectopia was documented in AIS patients. However, the tonsil position has not been clearly addressed in AIS patients with a severe curve.

METHODS

According to the method described by Aboulezz et al, measurements of the tonsil position relative to the magnum foramen on magnetic resonance images were performed in 203 AIS patients with a Cobb angle >40 degrees and 86 age-matched healthy adolescents. The inferior displacement of the cerebellar tonsil with an extent within 5 mm was defined as tonsillar ectopia when it located below the magnum foramen. On the basis of measurement results, the incidence of tonsillar ectopia was determined in both AIS and control groups. The associations of tonsillar ectopia with curve severity and curve patterns for AIS patients and the relationships of the tonsil positions with age and gender in all subjects were analyzed.

RESULTS

In AIS patients and healthy controls, the median position of the cerebellar tonsil was 0.8 and 2.9 mm above the magnum foramen, respectively. The incidence of tonsillar ectopia (0-4.8 mm below the magnum foramen) in AIS was found to be significantly higher than healthy adolescents (range 0-1.8 mm vs. 0-4.8 mm below the magnum foramen; ratio 34.5% vs. 5.8%; P < 0.01). No significant correlations were found between the position of the cerebellar tonsil with age or gender in AIS and control subjects. It was shown the position of the cerebellar tonsil was not significantly different among AIS patients with different curve severity. However, it was noted that there was a highest incidence (62.5%) of tonsillar ectopia in atypical scoliotic cases with a double thoracic curve. Additionally, a significantly higher incidence of tonsillar ectopia was found in patients with thoracic or thoracolumbar curves when compared with those with lumbar curves (37.4% vs. 21.6%, P = 0.049).

CONCLUSION

Tonsillar ectopia with the extent >2 mm in AIS patients should be regarded as abnormal. AIS patients had a lower tonsil position and a higher prevalence of tonsillar ectopia than controls, and tonsillar ectopia was found to be associated with curve patterns. It is suggested that a lower position of the cerebellar tonsil might be associated with the etiopathogenesis of AIS and might contribute to subclinical neurologic dysfunction in AIS patients.